Method preventing water bag deterioration



Patented Nov. 3, 1931 ERNEST T.HA1\TDLEY, or Axnon, orno, sssreivon TO THE FIREST'ONE TIRE & COMPANY; or AKRON, OHIO; A; CORPORATION or 01110 1 METHOD rnnvnivrr vea-wsrnn iazienn'rnn onarron No Drawing. Application filed March ,sipieaorseriai 1 0,440,634; enewed May 26,1931.

This invention relates to a methodfor preventing deterioration of water bags suchas used in the curing of pneumatic tiresi In the manufacture of pneumatic tires or similar hollow rubber articles vulcanized in steam-heated molds, it is the practiceto place an air or water bag made of rubber inside the tire during the cureito assist in forcing the rubber of the green or uncured tire, softened is by the heat of vulcanization, properly into the mold cavity. Air bags,'-whi'ch'are' rubber bags filled with compressed air, have proven satisfactory for this purpose but in the last few years the bags have been filled with very hot water under-"pressure which not only forces the tire to properly fill the mold cavity, but also serves to cure the tire from theinside while the steamheated mold cures the tire from the outside. This inside and out- 20 side heating or cure gives a more uniform and evenly vulcanized tire than was possible with the old air bag, however, the conditions to which the water bag is subjected tend to rapidly deteriorate it. This deterioration is primarily from the inside of the bag outwardly and is due to the oxidizing act10n of the free oxygen dissolved in the water circulated through the bag. The temperature and pressure of the circulating water assists this 3 oxidizing action so that after several cures the bags become so rotten that they will not hold the necessary pressure of the circulating water.

It is an object of the invention to overthe provision of an inexpensive eflicient process which prevents the oxidation and deterioration of the water bags under the necessary conditions of temperature and pressure.

The above and other objects of the invention are achieved by the method herein described, it being understood that the invention is not limited to exact details thereof described. 1

It has been found that by adding sodium sulphite (Na SO to the circulating water the interior oxidation of the water bagsis substantially prevented and that the lifeof the water bags is materially increased.

,In practicing the invention one-half ounce come the above difficulties of the prior art by of sodium sulphite will sufliciently deoxidize one gallonof circulating water so that it may be circulated through the water bags at ordinary vulcanization; temperature and without deterioration of the bags.

The above figures are, or course, for general conditions and may bewidely varied in actual practice as the temperatureand pres- ENT OFFICE pressure RUBBER f sure of the circulating water andthe compo- I,

sition of the water bag is changed.

The sodium sulphite may be introduced into the circulating water in any desired manner, such as dissolving it in water to give a concentratedsolution and continually or periodically injecting the concentrated water 'soluti'onin'to the circulating-water to give the' determined concentration therein or by passing the circulating water through-a bed or filter ofthe merely dump'ing the sodium sulphite crystals into the circulating water. v y The treate'dcirculating water can be continuously used fora plurality of cureswithout loss of the" properties thereof. Any nec essary loss in theamount of the circulating water can be periodically replenished. However, if necessary or desirable the treated circulating' water may be used for one cure' or is'in'expens'ive. v

' -While"the' invention has been particularly described with respect to the manufacture of pneumatic tiresit is evident that the princiforlonly' a short time asthe sodium sulphite v I V V sodium sulphite crystals or by ple's thereof may be applied to the manufacture of any curable bodies which are forced into the molds by a water bag. Again the principles of the invention may be applied wherever hot water under pressure comes in contact with rubber.

As many other changes 'couldbe made in the process, it is intended that all matter contained in the above descriptionshall be interpreted as illustrative only and not in a limiting sense, accordingly various modifications and applications of the invention can be resorted to without departing from the spirit of the invention or the scope of the appended claims. 1 i ;W.hat is'jclaimed isz. 1

1. In the manufacture ofipneumatictires' that method which-comprises placing a water bag inside the green moldable article, placing the moldable article and bag in a heated mold,

providing water for circulation through said water vbag, placing sodium sulphite in the water to deoxidize the same, and circulating said deoxidizedwaterthrough said bag under heat and pressure;

3.. In the manufacture of moldable articles that method which comprises placin-ga Water bag adjacent the green moldablearticle. placing the mold-able art cle and bag in :a heated mold, providing water for circulation through said water bag, placing sodium sulph t e n the water to deoXi-dizethe same, and circulating said deoxidized water through said jloag under heat and pressure. t

4. Inthe manufacture ofpn'eumatie tires that method which comprises placing a Water bag inside the green tire casing; placing the casing and bag in a heated-mold.- providing water to fill said water bag, placing sodium sulnh te in the water to deoxid ze the same, and filling said bag with said deoxrdized water under heat and pressure,

5. In the manufacture of moldable articles 7 that method which comprises placing a water water bags for curing, that method 7 using water hags 'for curing, that method which comprises circulating a solution of a 'sulphite of -analkali'metal through the water nsingiwater bags for curing,.that ;mjethod which comprises heating a solution of a sul- 1'2. In the vulcanization of rubberarticles phite alkali metal, and introducingsaid sol-ution into said water bag I 7 13. In the vulcanization-of rubber articles using water bags for curing, that method whichrcom-prises circulating water and a deoxidizing agent through the water bag.

14. In the; vulcanization of rubber articles using waterbags for curing, that method which comprises heating water and a deoxidizing agent, and introducing same into saidwater bag. g c I 15.. In the -vulcanization of rubber articles using water bags for curing, that method which comprises dissolving a soluble reducing agent in water, heating said solution. and introducing said solution-into said water bag. ERNEST T. HANDLEY.

bag inside the green moldable article, placing 7' the moldable article and bag in a heated mold, provid ng water to fill said water bag. placing sodium sulphite inthe water to deoxidize the same, and filling said bag with said deoxidized water under heat and pressure.

6. In the manufacture of pneumatic tires using rubber water bags for. curing. that method which comprises forming a solution of sodium sulphite -and circulating said solution under heat and pressure through the water bag used in the cure whereby the oxidation of the interior of the water bag is pre7zvented.

method which comprisesforminga solution of sodium sulphite, and circulatingsaid solution through the water bag used in the cure whereby the oxidation of the interior of the water bag is prevented.

8. In the manufacture of pneumatic'tires using rubber water bags for curing, that method which comprises forming a solution of sodium sulphite, heating said solution, and

In the manufacture of pneumatic tires using rubber water bags for cur1ng, ,that' circulating said solution under pressure I through the water bag used in the cure whereby the oxidation of the interior of the water bag is prevented. v 

